PVC and HDPE – Similar Yet Different

The underground piping market in North America has seen tremendous growth over the last 30 years in the use of thermo-plastic materials. Benefits such as corrosion resistance, improved hydraulics, and reduced installation costs have been paying large dividends for owners of watermain, sanitary and thunderstorm sewer systems. Broward County Fence

The most widely used and accepted of this group of nonmetallic polymers is Polyvinyl Chloride, also known as ‘PVC’ or ‘vinyl’. Plastic has a successful track-record in the application of underground pipe dating again to the rebuilding of post-WWI Germany. They have long been considered to be one of the very durable polymers for both underground and above-ground piping systems.

One other thermoplastic found in the undercover pipe companies are High-Density Polyethylene (HDPE). This fabric has recently been used for well tube, gas piping and draining tubing before recent admittance into the watermain and sewage forcemain markets.

HDPE and PVC are amazingly similar in their mother nature of responses to such stress loadings as inner pressure and soil lots. Although responses are very similar, they are not identical. In reality the variation of their respective talents are drastically different.

This kind of report is intended to review some of the parallels and distinctions between the design of PVC and HDPE in conditions of the application of subterranean pressure piping.

PRESSURE SCORE

The long-term pressure ranking of any thermoplastic pipe is defined as the most inner pressure at which the pipe can operate consistently. The ratings of both PVC and HDPE are simply using the ISO Formula for thermoplastics:

Equation (1) P = 2S as well as (DR-1)

where P sama dengan pressure rating of the pipe

S = design stress of pipe materials

DR = dimension proportion of the pipe, (OD/t)

The main difference between PVC and HDPE pressure capacity lies in the value of the design stress. For PVC 1120 compounds, the design stress is 2000 psi while that of HDPE 3408 is merely 800 psi. These types of design stresses were both derived in the identical fashion. A factor of security of 2. 0 was placed on the long-term hydrostatic strength (i. e. the Hydrostatic Design Basis – HDB) of each materials. The HDB for PVC 1120 is 4000 pound-force per square inch (psi) while regarding HDPE 3408 is 1600 psi.

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